Hydrocarbon oil conversion



March 6, 1934. J. D. sEGuY HYDROCARBON OIL CONVERSION Filed July 28, 1930 Patented Mar. 6, 1934 UNITED STATES PATENTg OFFICE This application isa continuation in part. of*

my copending applicationjserialfNo. 5,337, filed January 2a, 1925.' i 1 .j

My invention relates to a processor- ,cracking hydrocarbon oils, and more particularly "to a process which may becarried cutinatube and drum type of apparatus. It is amongthe objects of my inventionto provide a process in which I am enabled to pre.-

1 vent overcracking yof `the less .refractory constituents of the oil; to provide a process wherein carbon formation and deposition in the heating coil is substantially eliminated, as well as a proc-- ess wherein the production of fixed gases is materially lessened.

More specifically, my invention contemplates the superheating of a portion of vthe generated vapors and the return of such superheated generated vapors into the reaction drum to maintain the hydrocarbons therein at the optimum cracking temperature and to cause a re-combining of the superheated vaporous fractions with said hydrocarbons to materially increase the reaction and the yield of light' distillate and, in general, to provide a process and apparatus for the economic conversion of heavier into lighter hydrocarbons. f

My process is directed specifically to thesocalled non-residuum type of operation wherein so no liquid residue is withdrawn from the reaction drum. The coke formed accumulates in the reaction drum and is removed at the end of the run. With this type of operation a larger percentage of vapors, based on the raw oil charged,

are evolved and this'permits the treatment of a larger proportion of the material undergoing conversion in the vapor-phase heating elementi, giving added flexibility to the process in the production of anti-knock motor fuel.

o lFor the purpose of clearness and conciseness I will describe my process in connection with the apparatus disclosed' in the accompanying drawing which illustrates, diagrammatically and not to scale, a side'elevation, partly in section,

4 of an apparatus suitable for carrying out my process.

In carrying out the process, raw oil from anysuitable source of supply (not shown) is drawn through the lline 1 and forced by the pump 2 through the line 3 to the heating coil 7 or by proper regulation of the valves 5 and 6 the raw oil may be directed entirely through the line 4 to the top ofthe dephlegmator, or the stream' of raw oil may be divided, a portion thereof passY` ing directly through the line 3 to the inlet of the heatingfcoil, Vwhilethe remainingportion is directed through the line 4 to the top of the dephlegmator 18.,- 'I'he oil passingthrough the coil 7 disposed in thefurnace 8, heated by the burner 9, is'y raised tothe desired temperature. 60 The heated oil constituents are directed froml .the coil 'I through ythe transfer line `13 controlled by suitable throttle valve 14 to the enlarged reaction drum 15', wherein Aconversion takes place.

A portion of the evolved vapors passes from the 6:5l reaction'drum 15 through the Avapor line 1 6l controlled by valve 17 into the dephlegmating column 18. In this dephlegmator the "heavier" fractions of the vapors are condensed, forming reflux condensate, which is returned through the reflux leg 19 by means of the pump 2l to the raw oil charging line or it may be passed by grav' .4 ity through the by-pass line 22 by suitably regulating valves 20, 23.'and 24. The uncondensed vapors pass' from the dephlegmator 1 8 through the 75 line 25 in which is interposed a suitable throttle valve 25-a tothe final condenser 26 positioned in a condenser box 27. The pressure distillate and uncondensable gas pass from the condenser 26 through the line 28 controlled by valve 29 80 to the receiver 30. The receiver 30 is provided with liquid drawolf line 31 controlled by valve 32 and with uncondensable gas release line 33 controlled by valve 34, it being, of course, Vunderstood that thereceiver is provided with suitable liquid level and pressure gauges.

As a further feature of the invention the pressure distillate may be drawn oil through the line 35 controlled by valve 36 and forced by the pump 37 through the line 38 to the dephlegmator 18 to 90 act as a dephleg'mating and stabilizing medium for the generated vapors.

The feature of my invention .that I regardes most important, comprises they withdrawal of ay portion of the vapors from the reaction drum 15, the superheating of these vapors and their re.- turnto the reaction drum 15. To accomplish this I provide avapor draw-off line 39 which communicates 4with the vapor space of the reaction drum 15 and'iscontrolled by a suitable valve 40. 100

- This line 39 communicates with a'pump or blowerA 41 which vin turn connects to a'coil 42 disposed in the upper portion 10 of the furnace 8 in the pathof theV escaping combustion gases from the furnace. A burner. 11 ls provided for'applying 105 additional heat to this coil 42 in theY event it is found to bef necessary.v The vapors after' passing through the 'coil 42 are directed through line 43 controlled by valve 44to the reaction drum 15. It

will be readily apparentthat by this means aI llo portion of the generated vapors can be withdrawn from the reaction drum 15, superheated, and returned to the reaction drum.

Provision has been made for the withdrawal of unvaporized liquid residue through line 15' by proper manipulation of valve 15", but it is con templated operating the process of the invention as a non-residue operation. By non-residue operation I mean an operation wherein substantially no unvaporized liquid residue is withdrawn from the reaction drum 15. In some instances it'may be desirable, particularly in the start of a run, to withdraw a small amount of liquid residue, but non-liquid residue contemplates the Withdrawal of substantially no liquid residue. In a non-residue operation the coke producedL in the reaction drum is allowed to accumulate until the end of the run and in fact the cycle of operation is, in some cases, determined by the length of time required to ll the drum with coke.

The coke may be removed from the drum at the end of the run in any suitable manner, for example, by the use of a cable or other reticulated means distributed Within the drum and imbedded in the mass of coke formed during the operation, in such manner as to permit the removal of the coke when the cable is pulled.

The amount of carbon formed in the superheating of the vapors depends on the characteristics of the latter and on the degree of superheat given them. Due to the velocity and turbulency of the vapors passing through the superheating coil 42 and through line 43, the ne carbon particles are held in suspension and given no opportunity to adhere to the walls of the tube and will be to a considerable extent carried back into the reaction drum 15.

The particular conditions which will be maintained in the various parts of the apparatus, for example, the coil 7, the drum 15, and the coil 42, and also the proportion of the vapors superheated and re-injected into the reaction drum, lwill vary depending on the character and nature of the oil being treated.

In the operation of the process of my invention, differential or equalized pressures may be used, for example, the pressure on the oil heating coil may be higher than that in the reaction drum. Pump 4l permits the pressure on the vapor heating coil to be increased with respect tothat on the reaction drum. Similarly the dephlegmator, condenser and receiver may be at equalized pressures with respect to the reaction drum or at lower pressures.

'Ihe nature and character of my process can perhaps be best understood by comparing it with a process in which no portion of the vapors is reheated and recirculated to the reaction drum. The following is an example of such a run carried out in my apparatus. A Mid-Continent fuel oil having a Baume gravity of approximately 25.1` was subjected in the heating coil to a temperature of substantially 880 F. while the temperature in the reaction drum averaged substantially 850 F. The vapors leaving the reaction drum to enter the dephlegmator were at a temperature of substantially 840 F. This run was carried out under a pressure of about 150 pounds. Under this process about 50 per cent of the charge was converted into gasoline having an end point of 437 F., about 30 per cent of the charge was converted into gas oil, while the coke produced represented about 12 per cent. 'I'he uncondensable gas and dry coke amounted t@ 84.191.115 20 per cent of the oil charged.

For the purposes of comparison the following run is given, in which a portion 'of the vapors was withdrawn from the reaction drum 15, superheated, and returned to the reaction drum. In this run the same character of oil was treated. 'Ihe temperature to which the oil was subjected in the coil was substantially 850 F. The vapors which were superheated and returned to the drum were raised to a temperature of substantially 1100c F. These vapors were in the proportion of about 50 per cent of the amount of the oil passed through the coil by weight. The average temperature maintained in the reaction drum was substantially 900 F. while the vapors leaving the chamber to be directed either into the dephlegmator or into the vapor heating coil were at a temperature of substantially 875 F. In carrying out this last-mentioned run about 60 per cent of the oil charge was converted into gasoline, having substantially the same Baum characteristics as that produced in the preceding run, about 15 per cent of gas oil was produced, while dry carbon and uncondensable gas produced was about 25 per cent. The anti-knock value of the gasoline was increased from about 25 per cent to 35 per cent benzol equivalent in the second operation.

Ido not fully appreciate all of the reasons for the advantages obtained whena portion of the vapors is superheated and returned to the reaction drum. I do, however. know .that this operation when carried out as described gives the improved results.

It is my belief, however, that these advantages can beexplained in part by the law of mass action. The subjection of a portion of the vapors to the superheat action in the coil 42 has a tendency to additionally crack these vapors and to produce therefrom lighter or uncondensable gases and heavier portions or coke, which are normally end products formed in the main cracking zone. 'Ihe injection of the latter .into the reaction drum during the run will, according to the above law, greatly lessen the formation of further gas and coke to such an extent as to more than balance the quantities produced by the additional cracking of the vapors.

Furthermore, I believe that while it is true that some gases are formed in the passage of the vapors through the coil 42, these gases re-combine with heavier fractions o1' the hydrocarbons in the reaction drum 15 and result in the conversion oi' a greater percentage of the oil into light condensable fractions than can be obtained where no vapors and gases are reconverted and recirculated. The recirculation of the hot vapors and gases through the reaction drum 15 makes it possible to maintain the hydrocarbons therein at the optimum cracking temperature without necessitating the application of such a high heat to the oil in the coil 7 as to cause over-cracking of the less refractory constituents and formation of carbon in the heating element.

It is well recognized in oil treatment that the introduction oi' vapors or gas assists vaporization of substantial portions of the oil at lower temperatures owing to the partial pressure of the vapors or gas. In my process I' employ this phenomena to increase vaporization in the reaction drum without the necessity of heating the oil in the coil to such a high temperature as will cause coking of the tubes. My experience has also shown that the conversion of the hydrocarbons in the reaction drum is increased and accelerated by injecting heated vapors taken from the system into the reaction drum.

I claim as my invention: v 1. A hydrocarbon oil cracking process which comprises passing the oil in a restricted stream through a. heating zone and heating the same therein to cracking temperature under pressure, discharging the heated oil into a vapor separating zone and separating the same ,therein into vapors and unvaporized oii, removing the separated vapors from the separating zone, heating a portion of the withdrawn vapors to a vapor phase cracking temperature and then injecting the same into the unvaporized oil in said separating zone, the temperature and amount of the thus injected vapors being suiicient to distill the unvaporized oil substantially to dryness.

2. A hydrocarbon oil cracking process which comprises passing the oil in a restricted stream through a heating .zone and heating the same therein to cracking temperature under pressure, discharging the heated oil into a vapor separating zone and separating the same therein into vapors and unvaporized oil, removing the separated vapors from the separating zone, heating a portion of the withdrawn vapors to a vapor phasev cracking temperature and then injecting the same into the unvaporized oil in said separating zone, the temperature and amount of the thus injected vapors being suiiicient to distill the unvaporized oil substantially to dryness.' dephlegmating the remaining portion of the vapors withdrawn from the separating zone to condense insuiiiciently cracked fractions thereof, and vrel,949,765.-Jean Delattre Segu Chicago, Ill. HYnRocARBoN higher temperature than `the first-mentioned vapor phase suiiicient to distill the unvaporized oil to cracked vapors from said second zone in. amoun turning resultant reux condensate to the heating zone for retreatment in the process.

3. In a hydrocarbon oil cracking process of the character wherein the oil is heated to cracking temperature under pressure in a heating zone, the heated oil separated into vapors and unvaporized oil in a separating zone, and the separated vapors passed to 'a dephlegmating zone for partial condensation; the improvement which comprises diverting a portion of s'aid separated vapors from the dephiegmating zone and, prior to any condensation thereof, heating the same to vapor phase cracking temperature, and injecting the thus heated vapors into the unvaporized oil in said separating zone, the temperature and amount of the diverted and heated vapors being suiiicient to distill the unvaporized oil to a nonowing residue.

4. A hydrocarbon oil cracking process which comprises passing the oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under suiiicient pressure to maintain a substantial portion there- 'of in the liquid phase', discharging the heated oil into a separating zone and separating the same into vapors and unvaporized oil therein, simul- .taneouslyheating hydrocarbon vapors to vapor phase cracking temperature in a second heating zone maintained at higher temperature thanthe first-mentioned heating zone, and injecting resultant vapor phase cracked vapors from said second zone in amount and at a temperature sumcient to distill the unvaporized oil vto coke.

JEAN DELA'I'IRE SEGUY.

MER

OIL CONVERSION.

6, 1934; Disclaimer filed June 4, 1935 b the t t Oil Products Company, consenting. y .f pa en ee,

of the claim in saidspecication which simultaneou l y vapors to vapor phase-cracking temperature a second s y heatmg hydrocarbon y u heating z one maintained-at heating zone, and injecting resultant t and at a temperature 

